The invention relates to improvements in machines for slicing pieces of meat or the like, especially to improvements in machines for skinning (derinding) or slicing bacon.
A bacon skinning or slicing machine normally comprises a so-called traction wheel which advances the product to be skinned or sliced against the cutting edge of a blade. The blade is mounted in a holder which is preferably adjustable so as to select the thickness of the slices or slabs which are being severed from the product. In many instances, the holder for the blade constitutes a balance beam which is tiltable in the machine housing or frame about an axis located at a level above the blade. As a rule, the blade is movable between a first position which it assumes during the initial stage of a slicing or skinning operation, and a so-called working position. The blade changes its position in response to engagement with the product, and its holder is normally mounted in a support which is provided with a bearing for the holder. Machines of such character can be used for the slicing or skinning of bacon, for removing skin from meat, for removing skin from fish and for similar purposes. In most instances, such machines are used for cutting slabs of bacon into slices and/or for removing skins or rinds from slabs of bacon.
Common owned German Pat. No. 1 278 873 to Schill discloses a bacon skinning machine which is provided with automatic blade orienting means, i.e., the orientation of the blade relative to the traction wheel changes as a function of characteristics of the product which is being treated in the machine. The arrangement is such that the blade is initially maintained in a position close to the traction wheel and is thereupon shifted by the product in the direction of advancement of the product through the machine. This causes a lifting of the cutting edge of the blade above and away from the periphery of the traction wheel so that the distance between the traction wheel and the blade increases. Such mode of operation is proposed in order to ensure that the cutting edge of the blade will move away from the relatively hard layer of bacon in close proximity to the rind and will begin to sever a softer layer which is located at a somewhat greater distance form the rind. One or more springs can be employed to pull the support for the holder in a direction to move the cutting edge of the blade nearer to the traction wheel. The spring or springs are designed to overcome the relatively low resistance of a softer layer or softer layers of the product to the penetration of the cutting edge of the blade thereinto. Such spring or springs are designed to urge the blade substantially to or close to the starting position in conformance to the thickness of the rind.
The just described machine operates satisfactorily if successively treated products (such as slabs of bacon) exhibit identical or very similar characteristics, particularly as concerns the hardness of material which is to be severed during transport through the machine. However, the operation of such machines is less reliable if a relatively soft slab of bacon is followed by a thoroughly aged slab which is much harder as a result of prolonged curing and/or storage. This will be readily appreciated since the extent of changes of orientation of the blade relative to the traction wheel during severing of a relatively soft slab of bacon is quite different from the extent of changes of orientation if the machine is called upon to skin a relatively hard product. In addition, and since the blade must move first from a starting position to the working position and thereupon back to the starting position, the length of that portion of the rind which is removed during the initial stage of the skinning or derinding operation (i.e., while the blade is in the process of assuming and remaining in its optimum position) is too long.
Commonly owned German Pat. No. 1 293 635 to MAJA discloses a skinning machine wherein the blade holder is confined to movements relative to a guide which causes the cutting edge of the blade to advance along an arcuate path. The curvature of the path resembles that of the peripheral surface of the traction wheel and is such that the cutting edge of the blade gradually approaches the traction wheel. A drawback of this machine is that the length of the initially severed portion of the skin, i.e., of the portion which is removed while the blade is in the process of moving toward its final position relative to the traction wheel, is still too long. Moreover, the machine of MAJA is not provided with any means for adjusting the holder for the blade in dependency upon variations of thickness of the skin or rind on a slab of bacon which is being advanced through the machine, i.e., toward and into the range of and thereupon by the rotating traction wheel.
Published German patent application No. 32 13 730 of Weber discloses a slicing or skinning machine wherein the position of the blade relative to the traction wheel varies as a function of changes in the force which is necessary to rotate the traction wheel, i.e., in dependency on the magnitude of resistance which the product offers to the slicing or skinning action. The position of the blade can be changed by pneumatic or electrical means. Such machines are overly sensitive and hence prone to malfunction, especially when used for the skinning or slicing of slabs of varying hardnesses and when manipulated by semiskilled or unskilled persons. Moreover, the cost of control means is high and the energy requirements of the machine are excessive.
Further presently known machines for slicing and/or skinning bacon or other edible products are disclosed in commonly owned U.S. Pats. Nos. 4,123,959, 4,188,870, 4,408,519 and 4,466,344, all granted to Schill. U.S. Pat. No. 4,466,344 discloses a machine wherein the blade is movable with reference to the traction wheel by a support having two arms which carry the holder for the blade. The support can be moved between a position in which the blade and the holder can be detached from the support, a starting position, and to a position in which the blade automatically conforms its position to the thickness of the rind on a slab of bacon. The disclosures of all four patents to Schill are incorporated herein by reference.